Fluid pumps, compressors or motors



June 13, 1961 F. w. MOCOMBIE FLUID PUMPS, COMPRESSORS OR MOTORS 2 Sheets-Sheet 1 Filed Dec. 10. 1957 FIG.1.

m m j 1 Q t 3/ r M l J. :i w r r I? i F 3 2 m n. g l? 1 i F: J m a m June 13, 1961 F. w. M COMBIE 2,988,011

FLUID PUMPS, COMPRESSORS 0R MOTORS Filed Dec. 10. 1957 2 Sheets-Sheet 2 FIG.2.

AFUQI y United States Patent 2,988,011 FLUID PUMPS, COMPRESSORS 0R MOTORS Frederick Walter McCombie, London, England, assignor to Megator Pumps and Compressors Limited, London,

England Filed Dec. 10, 1957, Ser.'No. 701,769 Claims priority, application Great Britain Dec. 13, 1956 7 Claims. (Cl. 103-163) The chief object of the present invention is to evolve an improved form of fluid pump, compressor, or motor of the kind including a plurality of pistons, each reciprocally mounted its own associated cylinder.

A fluid pump, compressor, or motor in accordance with the invention, includes two or more parallel shafts interconnected to revolve in unison in the same direction and each carrying a crank-pin or eccentric, the crank-pins or eccentrics on adjacent shafts occupying the same angular position, and being coupled by a connecting rod or link which, during rotational movement of the shafts, will have a non-rotational movement in a circular path, the connecting rod or link carrying an in tegral or separately formed piston or pistons reciprocal within an associated cylinder or cylinders, said cylinder or cylinders being each reciprocal over a port plate or its equivalent having fluid inlet and delivery ports with which the port or ports in the cylinder alternately register to control the entry of fluid into the cylinder, and the delivery of fluid from the cylinder, under the displacement action of its associated piston.

Although the shafts may be interconnected by means, for example, of a train of gears, it is preferred that each shaft shall carry two or more crank-pins or eccentrics arranged at a suitable angle relative to one another. For example, each shaft may have two crank-pins or eccentrics arranged at 90 to one another, or alternatively, and in a preferred embodiment, three crank-pins or eccentrics may be employed, arranged at 120 to one another. Alternatively, any other number may be used arranged at a suitable angle. It will be appreciated that with such an arrangement, the connecting rods or links will always move in a circular path with a non-rotational movement.

In the case of a pump or compressor, one shaft may be provided with an extension driven by an external source of power, and in the case of a motor, one or both shafts can be used to transmit power developed by the motor.

Referring to the drawings:

FIGURE 1 is a vertical section of a fluid compressor in accordance with the present invention mounted a reservoir or accumulator; and

FIGURE 2 is an enlarged transverse section taken on the line 22 in FIGURE 1.

The invention will be hereinafter described as applied to the construction of a fluid compressor in which the compressor is associated with a reservoir or accumulator inwhich fluid pressure will be built up, the reservoir or accumulator containing liquid at its lower end, the compressor being therefore fully immersed in liquid during its operation.

It will, however, be appreciated that the main constructional parts of the apparatus will be identical or substantially identical whether or not the apparatus is being used as a compressor, a pump, or alternatively a fluid driven motor.

In the construction illustrated, the compressor includes two parallel shatts 1 and 2, carrying eccentrics -3 and 4, opposite eccentrics being connected by means of a connecting rod or link 5.

In the arrangement shown, three eccentrics are associated with each shaft, adjacent eccentrics being arranged at an angle of 120 relative to each other.

Each connecting rod 5 carries a pair of pistons 6 which may be constructed integrally with the connecting rod or secured thereto, each piston reciprocating within an associated cylinder 7. The pistons and their associated cylinders may be composed of metal or other suitable material and may comprise any desired construction for sealing purposes and withstanding wear.

The cylinders will have a vertical reciprocatory movement imparted to them under the action of the revolving eccentrics 3 and 4, the cylinders engaging port plates 8 formed with inlet and exhaust ports 9 and 10, the cylinders opening and closing the inlet and exhaust ports at the appropriate times to draw in fluid through the ports 9 and under the. displacement action of the pistons force the fluid out of the exhaust ports 10 into the interior of a casing 11 which is formed with outlet openings 12.

Shafts 1 and 2 are revolvably mounted bearings 13 and 14 in the casing and shaft 1 projects from the casing and may carry a pulley or other driving member (not shown) by means of which shafts 1 and 2 can be driven, the angular disposition of the eccentrics on each shaft ensuring accurate movement of the connecting rods 5 in a non-rotational sense along a circular path.

To prevent rotational movement of the cylinders 7, each cylinder is provided with a recess 16 for receiving a guide pin 15 which may also function to retain the cylinder against the port plate. To reduce the size of the cylinders and their recesses to a minimum, the guide pins 15 conveniently may be carried by the respective connecting rod 5 so that the pins travel with the cylinders.

As the pressure of fluid at the outlet end of the compressor' is relied on to maintain sealing engagement between the cylinders and the port plates 8, and this pressure will be virtually non-existent during rotation of the compressor, each cylinder is provided with an extension 17 which makes rubbing contact with shaft 1 during this rotational movement of the compressor when the pressure of fluid is being built up. Consequently, during initial operation of the compressor a sufficiently good seal be obtained between the cylinders and their port plates to ensure operation of the apparatus as a fluid compressor. 7 Instead of mounting pins 15 on the connecting rod or link they may alternatively be carried by the casing, in which case they may perform the dual function of preventing rotational movement of the cylinders and maintaining the cylinders in sufliciently close contact with the port plates to ensure a good seal during initial operation'be'fore pressure has been built up.

The casing 11 is constructed integrally with a flange 18 w ich canbe. bo ed. by eans'efi t 9 0a an 2 on the reservoir 'or accumulator 21, the reservoir or accumulator containing liquid at its lower end and indicated generally by reference numeral 22.

It will be appreciated, therefore, that all the working parts of the compressor will be immersed in liquid which will provide the necessary lubrication between the pistons, cylinders, port plates, eccentrics and their associated connecting rods. To prevent escape of the liquid, however, from the casing and to maintain lubricant in the bearings 14, the ends of the casing 11 are closed by cover plates 23, the shaft 1 being fitted at its ends with sealing glands 24. A pipe 25 is provided leading from the inner end of shaft 1 to atmosphere to balance shaft 1 axially and avoid the use of end thrust bearings.

In operation, the fluid which is to be compressed enters by way of the fluid inlet connection 26, the fluid thence passing through oppositely positioned transverse fluid inlet passages 27 to the interior of side cover plates 28 each formed with three further fluid inlet passages 29 leading to fluid inlet ports 9. Consequently, the fluid appropriate position, can enter the cylinder 7, the inlet port being then closed, outward movement of the piston compressing the fluid within the cylinder and finally when the cylinder has moved to uncover the exhaust port 10, forcing'the fluid out of the exhaust port into themterior of casing 11. In this connection it will be appreciated that as the main parts of the apparatus will be immersed in liquid, the fluid will pass upwardly into the interior of the reservoir through the contained liquid and the pressure of fluid exerted on the surface of the liquid will ensure that the liquid will exert pressure on the inner ends of the cylinders suflicient to maintain a good seal between the outer ends of the cylinders and the port plates.

Although in the construction shown a comparatively simple type of compressor is illustratedinvolving three eccentrics on each shaft, each connecting membercarrying a pair of pistons, but obviously many equivalent 'variations may be effected without departing from the concept of the invention.

In the caseof a pump or motor, it will be unnecessary toprovide the external reservoir or accumulator and consequently the casing 11. will not be provided with delivery openings 12 but will be fitted with a pipe or other connection through which the fluid can pass after passage through the cylinders. When used as a fluid motor, shaft 1 will be provided with a pulley or other device forming a power take-off point.

It will be appreciated that the pump, compressor or motor as hereinbefcre described will be operating in an immersed condition in a liquid such as for example water. Consequently the liquid will ensure a good seal between the working parts and will itself provide the necessary lubrication properties for such parts, the gaseous fluid which has been compressed escaping to the surface of the liquid. This is particularly important in the case of a compressor for gaseous fluids or a pump during the priming period as any leakage or slip between the working parts will be the immersed liquid as distinct from the gaseous fluid,

. The loss of capacity resulting from such leakage or slip will therefore be very much reduced.

I claim:

l. A fluid pump, compressor or motor comprising a casing having inlet and discharge openings, parallel shafts rotatably mounted within said casing, a plurality of pairs of eccentrics with one of each pair mounted on each of said shafts, means including a link enclosing and connecting each pair of eccentrics on the adjacent shafts with the pairs of eccentrics always occupying the same angular position on their respective shaftsfor causing rotational movement of said shafts in unison and in the sarne'direc5 tion, pistons carried by each of said links, port plates in said casing each provided with inlet and delivery ports respectively in communication with said inlet opening and with the casing for exhaust through said discharge 4 opening and a plurality of cylinders each containing one of said pistons and each being slidably mounted over one of said port plates to open and close the inlet and delivery ports of the respective plate and alternately connecting said inlet and delivery ports with the interior of the cylinder, whereby the combined reciprocatory movement of the pistons within their corresponding cylinders and the reciprocatory movement of the cylinders over their corresponding port plates will cause fluid to enter said cylinders and then be discharged in the casing.

2. A fluid pump, compressor or motor as claimed in claim 1, wherein the cylinders are normally maintained in contact with the port plates by fluid pressure but are provided with extension pieces engageable with the shaft before the pressure of the fluid has built up to maintain the cylinders in sufficiently closev contact with the port plates to ensure a sufliciently good seal during the initial operation of the pump, compressor, .or motor.

3..A fluid pump, compressor or motor as claimed in claim 1, including guiding means engaging each cylinder for preventing rotational movement thereof in relation to its associated port plate. t

4. A fluid pump, compressor or motor as claimed in claim 3, wherein the guiding means for each .cylinder comprises. a pin extending from the associated link and projecting into an opening in the cylinder. 7 .5.. A fluid pump, compressor or motor as claimed in claim 1, wherein the cylinders have a common rnain inlet for fluid leading to branch inlet ports. in the port plates, theopening of which ports are under the control of said cylinders actuated by the reciprocating pistons, said casing defining a common pressure chamber, each cylinder exhausting through a port in the port plates leading to said common chamber in which fluid pressure can build up to maintain a good seal between the cylinders and port plates.

I 6. A fluid compressor as claimed in claim 5, including a reservoir, said casing being mounted in said reservoir with said discharge opening in communication with said reservoirtand through which the fluid after compression can pass into said reservoir.

' 7. A fluid compressor as claimed in claim 6, wherein thecasing is provided with a flange, means for securing said. flange to a flange on the reservoir so that the casing projects into the interior thereof, the flange on the casing having a connection with said inlet opening for the entry of the. fluid which is to be compressed. '5

' References Cited in the file of this patent UNITED STATES PATENTS, 1,601,370 Oden Sept. 28, 1926 1,645,834 Voreaux Oct; '18; 1927 2,055,046 Phillips et'al Sept.' 22, 1936 =2;1'07,344

Rodeghier Feb. 8, 1 938 

